Adaptability variations and differences in photoprotection of young leaves of two tree species of subtropical forest to the light environment

In the high-light environment, young leaves accumulate anthocyanins as a photoprotection strategy. However, anthocyanin biosynthesis-related enzymes gene sequence is still unknown in the leaves of subtropical forest plants. There are thus few reports on the relationship between the expression level of these genes and photoprotection. In this study, Machilus chinensis and Castanopsis chinensis were taken as plant material in a subtropical forest. Non-full-length nucleotide sequences of chalcone synthase, dihydroflavonol 4-reductase, anthocyanin synthase, and β-tubulin gene were obtained by homologous and electronic cloning. The expression of those genes was verified and analyzed, and some physiological indicators were measured. The anthocyanin content and anthocyanin synthesis-related gene expression in the young leaves of C. chinensis were significantly higher than that of M. chinensis. Although young leaves of M. chinensis did not accumulate anthocyanins, they showed higher antioxidants and nonphotochemical quenching (NPQ). This study indicates that anthocyanins, antioxidants, and NPQ together mediate the positive effects on photoadaptation in young leaves.